75
Manufactured under license from Dolby Laboratories.
“Dolby”, “Pro Logic” and the double-D symbol are trademarks of Dolby Laboratories.
Confidential Unpublished Works. ©1992-2000 Dolby Laboratories. All rights reserved.
w Dolby Pro Logic II
• Dolby Pro Logic II is a new multi-channel playback format developed by Dolby Laboratories using feedback logic steering technology and
offering improvements over conventional Dolby Pro Logic circuits.
• Dolby Pro Logic II can be used to decode not only sources recorded in Dolby Surround ( ) but also regular stereo sources into five
channels (front left, front right, center, surround left and surround right) to achieve surround sound.
• Whereas with conventional Dolby Pro Logic the surround channel playback frequency band was limited, Dolby Pro Logic II offers a wider
band range (20 Hz to 20 kHz or greater). In addition, the surround channels were monaural (the surround left and right channels were
the same) with previous Dolby Pro Logic, but Dolby Pro Logic II they are played as stereo signals.
• Various parameters can be set according to the type of source and the contents, so it is possible to achieve optimum decoding (see page
57).
Sources recorded in Dolby Surround
These are sources in which three or more channels of surround have been recorded as two channels of signals using Dolby Surround
encoding technology.
Dolby Surround is used for the sound tracks of movies recorded on DVDs, LDs and video cassettes to be played on stereo VCRs, as
well as for the stereo broadcast signals of FM radio, TV, satellite broadcasts and cable TV.
Decoding these signals with Dolby Pro Logic makes it possible to achieve multi-channel surround playback. The signals can also be
played on ordinary stereo equipment, in which case they provide normal stereo sound.
There are two types of DVD Dolby surround recording signals.
q 2-channel PCM stereo signals
w 2-channel Dolby Digital signals
2 Sources recorded in Dolby Surround are indicated with the logo mark shown below.
Dolby Surround support mark:
(2) DTS Digital Surround
DTS Digital Surround (also called simply DTS) is a multi-channel digital signal format developed by Digital Theater Systems.
DTS offers the same “5.1” playback channels as Dolby Digital (front left, front right and center, surround left and surround right) as well as
the stereo 2-channel mode. The signals for the different channels are fully independent, eliminating the risk of deterioration of sound quality
due to interference between signals, crosstalk, etc.
DTS features a relatively higher bit rate as compared to Dolby Digital (1234 kbps for CDs and LDs, 1536 kbps for DVDs) so it operates with a
relatively low compression rate. Because of this the amount of data is great, and when DTS playback is used in movie theaters, a separate
CD-ROM synchronized with the film is played.
With LDs and DVDs, there is of course no need for an extra disc; the pictures and sound can be recorded simultaneously on the same disc,
so the discs can be handled in the same way as discs with other formats.
There are also music CDs recorded in DTS. These CDs include 5.1-channel surround signals (compared to two channels on current CDs). They
do not include picture data, but they offer surround playback on CD players that are equipped with digital outputs (PCM type digital output
required).
DTS surround track playback offers the same intricate, grand sound as in a movie theater, right in your own listening room.
2 DTS compatible media and playback methods
Marks indicating DTS compatibility: and .
The following are general examples. Also refer to the player’s operating instructions.
e Dolby Headphone
• This is a three-dimensional sound technology developed jointly by Dolby Laboratories and Lake Technology Ltd. of Australia for achieving
surround sound using regular headphones.
• Previously, when using headphones all the sounds resonated inside the head and it was uncomfortable to listen over headphones for
long periods of time. Dolby Headphone simulates speaker playback in a room and places the sound at the front or the sides, outside the
head, to achieve a powerful sound like the sound of movie or home theaters. This technology is mainly for multichannel audio/video
equipment with Dolby Digital or Dolby Pro Logic Surround decoding functions and works with a high performance digital signal
processing (DSP) chip.
• Dolby Headphone is effective not only for multichannel sources but also for stereo programs.
• On the AVR-5803, it is possible to output signals encoded in the Dolby Headphone mode from the recording output terminal and record
them on a separate recorder.
